Fermented wheat flour may be safe for celiac patients, suggests study

Baked goods made from wheat flour fermented with certain micro-organisms may be tolerated by celiac disease patients, according to new research.

The study, published in Clinical Gastroenterology and Hepatology, evaluated the safety of daily administration of baked goods made from a hydrolyzed form of wheat flour to patients with celiac disease – finding that fermented wheat flour with sourdough lactobacilli and fungal proteases decreases the concentration of gluten to safe levels.

“This is the first time that a wheat flour-derived product is shown to not be toxic after being given to celiac patients for 60 days,” said Dr Luigi Greco, of the University of Napes, Italy, lead author of the study.

Greco said that the study’s findings support the need for further research to explore therapies that could reduce the toxicity of gluten for celiac patients, beyond a standard gluten-free diet.

“In the future, cereals made through such biotechnology could also improve the nutritional and sensory properties of baked goods containing hydrolyzed gluten compared to products made of naturally gluten-free ingredients," added Greco.

Gluten problem

Celiac disease occurs in the digestive system when people cannot tolerate gluten, a protein in wheat, barley, rye and spelt. The disease is characterized by an inflammatory response to gluten-containing products.

The researchers said that currently, cereal baked goods are manufactured by fast processes. Because of this traditional long fermentation by sourdough – a cocktail of acidifying and proteolytic lactic acid bacteria – has been replaced by chemical and baker's yeast leavening agents. Under these conditions, cereal components are not degraded during manufacture, said Greco and colleagues.

Previous research has shown that the manufacture of wheat and rye breads or pasta with durum flours by using selected sourdough lactobacilli markedly decreased the toxicity of gluten.

The new study evaluated the safety of a daily administration to celiac disease patients (for 60 days) of goods made of wheat flour hydrolyzed during food processing by a mixture of selected sourdough lactobacilli and fungal proteases.

Study details

The Italian researchers evaluated the effects on 16 otherwise healthy patients with celiac disease, who had been on a gluten-free diet for at least five years.

The authors reported that two of the six patients on the natural flour diet discontinued the study because of symptoms such as malaise, abdominal pain and diarrhoea. All of the patients consuming natural flour were found to have increased levels of anti–tissue transglutaminase (tTG) antibodies and small bowel deterioration.

Patients who ate extensively hydrolyzed flour reported no clinical complaints, but were found to have developed subtotal atrophy – complete absence of the fingerlike protrusions in the gut that necessary for absorption.

The five patients that ate the fully hydrolyzed baked goods reported no clinical complaints, and were found to have no changes in the levels of anti-tTG antibodies.

Non toxic

The authors concluded that a 60-day diet of baked goods made from hydrolyzed wheat flour, manufactured with sourdough lactobacilli and fungal proteases, was not toxic to patients with celiac disease.

“A period of 60 days, although repeatedly shown to be sufficient to evaluate gluten toxicity in the majority of patients, might not be long enough to evaluate toxicity in all celiac disease subjects who might show different sensitivity to gluten,” said the researchers.

“Prolonged trials have to be planned to state the safety of the baked goods manufactured by applying this rediscovered and adapted biotechnology,” they added.

Great hopes for sourdough

Sourdough has already been identified as an ideal gluten-free food. Indeed, Professor Elke Arendt from the Department of Food and Nutritional Science at University College Cork co-authored a review in the journal Food Microbiology (Vol. 26, pp. 676-684) on the how sourdough could help solve the gluten-free issue.

Prof Arendt told FoodNavigator in 2009: “Sourdough has a lot of potential, particularly from a flavour and structure perspective. The strains used are also anti-fungal and that can extend the shelf-life of bread without the need of chemical preservatives.”

“I have great hopes for sourdough in gluten-free bread,” she said.

Allergies and intolerances

FoodNavigator.com will be addressing formulation and labelling of allergens - and nutrients to which some individual are intolerant - at its forthcoming Allergen-free Foods conference, taking place in London on 31st March 2011.